1. Field of the Invention
The present invention generally relates to an input device used in a computer system, and particularly relates to a pointing device for moving a cursor to a desired position in a display and to an acceleration-measuring apparatus.
2. Description of the Related Art
Recently, many computer systems are provided with pointing devices as well as keyboards, so as to provide a data input means of an improved operability.
Pointing devices such as mouses and digitizers have been commonly used for desktop type computers. However, laptop type or notebook type portable computers require pointing devices which can be used at places where no flat working surface is available.
Thus, various pointing devices, such as a track-ball type pointing device, which are reduced in size and do not require a flat working surface have been developed.
FIG. 1 is a diagram showing an example of a pointing device 100 of the related art.
As shown in FIG. 1, the pointing device 100 of the related art is provided with a rod 101. The rod 101 and a supporting frame 102 are connected via a tightly wound coil spring 103.
A coordinate detecting part 104 is provided underneath the rod 101 and the supporting frame 102. The coordinate detecting part 104 includes, for example, a light-emitting element 105 provided at a lower end of the rod 101 and a light-receiving element 106 mounted on a printed-circuit board 107 at a position opposing the light-emitting element 105.
The light-receiving element 106 may be a CCD having a number of light-receiving parts arranged in a matrix form. When the rod 101 is pushed in a desired direction with a horizontal force, the coil spring 103 is bent and a shaft center of the operating rod 101 is tilted. Thus, a direction of irradiation of the light-emitting element 105 changes.
As a result, corresponding to a direction and an angle of inclination, a light beam from the light-emitting element 105 is incident on a specific light-receiving part on the light-receiving element 106. Then, electric signals are output from the light-receiving parts provided on the light-receiving element 106 at positions corresponding to coordinates of the direction and the angle of inclination of the rod 101.
The above-described pointing device 100 of the related art has comparatively large size and weight. Therefore, the pointing device of the related art is cumbersome and difficult to handle with ease. That is to say, there is a problem that the pointing device is not suitable for use by small children.
Therefore, there is a need for a pointing device which is usable for all ages. Further, there is a need for a pointing device with a reduced size and a good operability.
Accordingly, it is a general object of the present invention to provide an input device which can satisfy the needs described above.
It is another and more specific object of the present invention to provide an input device having an operating part which returns to its initial position when released.
In order to achieve the above objects, an input device includes a substantially spherical part provided at a lower end of said movable part; bearing means which rotatably supports said substantially spherical part of said movable part; a recovery means which rotates said substantially spherical part within said bearing means so as to recover the upright position of the movable part; and inclination detecting means which detects a direction of inclination and an angle of inclination of said movable part.
The input device described above may be embodied as a pointing device or as an acceleration measuring device. With the structure describe above, it is possible to obtain an input device with a reduced size.
The recovery means may include a cover having a cylindrical part; a plurality of protrusions protruding outward from said substantially spherical part; a slider slidably provided in said cylindrical part of said cover, a lower end of said slider being supported by said protrusions; and a spring which downwardly spring-biases said slider.
With the recovery means described above, the input device can be operated with less operational force. Further, it is ensured that the slider and the movable part will recover its original position.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.